This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 3 |
| 1 | 25 |
| 2 | 117 |
| 3 | 405 |
| 4 | 1155 |
| 5 | 2871 |
| 6 | 6435 |
| 7 | 13299 |
| 8 | 25740 |
| 9 | 47190 |
| 10 | 82654 |
| 11 | 139230 |
| 12 | 226746 |
| 13 | 358530 |
| 14 | 552330 |
| 15 | 831402 |
| 16 | 1225785 |
| 17 | 1773783 |
| 18 | 2523675 |
| 19 | 3535675 |
| 20 | 4884165 |
| 21 | 6660225 |
| 22 | 8974485 |
| 23 | 11960325 |
| 24 | 15777450 |
| 25 | 20615868 |
| 26 | 26700300 |
| 27 | 34295052 |
| 28 | 43709380 |
| 29 | 55303380 |
| 30 | 69494436 |
| 31 | 86764260 |
| 32 | 107666559 |
| 33 | 132835365 |
| 34 | 162994065 |